The present invention generally relates to an apparatus, a system and a method for motion compensation using wired drill pipe. The wired drill pipe may transmit measurements from downhole tools to the surface and control signals from a terminal located at the surface to the downhole tools. The measurements and the control messages may enable the drill string to compensate for motion, such as, for example, heave.
To obtain hydrocarbons in water environments, a wellbore may be drilled in a subsea floor using a drill string lowered from a floating platform, such as, for example, a drilling ship or a floating rig. The drill string is a continuous length of pipe made by connecting segments of pipe end to end. The drill string may be suspended from the floating platform by a hoisting system. The drill string is driven into the subsea floor to form the wellbore through which the hydrocarbons are extracted. A drill bit is attached at a lower end of the drill string, and a bottom hole assembly (BHA) is located proximate to the drill bit.
The BHA consists of tools which generate and/or obtain measurements related to wellbore operations, such as, for example, drift of the drill bit, inclination and azimuth. For example, it is known in the art to use “wireline” conveyable well logging instruments using drill pipe as the conveyance. Such conveyance is used where gravity alone is insufficient to move the logging instruments along the wellbore when conveyed by armored electrical cable (“wireline”). Such conveyance has particular application in highly inclined wellbores. See, for example, U.S. Pat. No. 5,433,276 issued to Martain et al.
It is also known in the art to use “logging while drilling” (“LWD”) instruments. LWD instruments are disposed in one or more drill collars which are thick-walled segments of pipe having threaded connections at the longitudinal ends of the segments. The collars are coupled into the drill string such that lowering the drill string into the wellbore moves the LWD instruments past formations adjacent to the drill string. The sensors of the LWD instruments may obtain measurements of selected properties of the formations.
The floating platform intermittently moves up and down as a result of wave motion, known to one having ordinary skill in the art as “heave.” The heave of the floating platform creates difficulties in conducting the wellbore operations and may require that the wellbore operations cease. For example, the heave of the floating platform may damage the drill string and the tools connected to the drill string.
More specifically, the distance between the floating platform and the subsea floor may be variable due to the heave of the floating platform. Therefore, upward movement of the floating platform induced by the heave may raise the drill string in the wellbore, and downward movement of the floating platform may lower the drill string in the wellbore. Raising and lowering the drill string in response to the heave may damage the drill string and the tools. For example, raising the drill string may impart tensile stress to the drill string, and lowering the drill string may impart compressive stress to the drill string.
In addition, the heave may prevent the drill bit from maintaining a position at the bottom of the wellbore. For example, each time a wave raises the floating platform, the floating platform may pull the drill bit in an upward direction, and each time a wave lowers the floating platform, the floating platform may push the drill bit in a downward direction. Thus, the heave may vary the weight-on-bit, may lift the drill bit away from the bottom of the borehole, and may damage the drill bit by forcing the drill bit against the bottom of the borehole.
Accordingly, a failure to effectively respond to the heave may be costly. The heave may create a need to replace or repair the drill string and the tools and may ultimately decrease hydrocarbon production from the wellbore operations.
Technology for transmitting information from the tools while the tools are located within the wellbore, known as telemetry technology, is used to transmit the measurements from the tools of the BHA to the floating platform for analysis. U.S. Pat. Nos. 6,641,434 and 6,866,306 to Boyle et al., both assigned to the assignee of the present application and incorporated by reference in their entireties, describe a wired drill pipe joint that is a significant advance in the wired drill pipe art for reliably transmitting measurement data in high-data rates, bidirectionally, between a surface station and locations in the wellbore. The '434 patent and the '306 patent disclose a low-loss wired pipe joint in which conductive layers reduce signal energy losses over the length of the drill string by reducing resistive losses and flux losses at each inductive coupler. The wired pipe joint is robust in that the wired pipe joint remains operational in the presence of gaps in the conductive layer. Advances in the drill string telemetry art provide opportunity for innovation where prior shortcomings of range, speed, and data rate have previously been limiting on system performance. Accordingly, wired drill pipe may enable rapid transmission of signals that may be used for improved motion compensation.